1. Field of the Invention
This invention relates to capstans for use in handling slitting tools for sheet metal slitter machines, and more particularly, to a novel capstan capable of vertical guided movement so as to permit its use at a height convenient to an attendant.
2. Description of the Related Art
A slitter machine uses rotary slitting knives or tools for cutting of sheet metal into strips. More specifically, a plurality of knives and spacers having center holes are slid onto arbors or shafts of the slitter machine. Typically, a slitter machine will include pairs of vertically-spaced arbors. Each arbor induces the knives to rotate as the arbor is turned. The rotating knives cut sheet metal into a plurality of xe2x80x9cmultsxe2x80x9d as the sheet metal passes between the arbors. The arrangement of the knives and spacers on the arbors of the slitter machine must be changed when it is desired to change the number or relative sizes of the mults cut from the sheets passing between the arbors.
A capstan is often used in removing and replacing the knives and spacers. Known capstans include a capstan frame and shafts or arbors which extend from the capstan frame in alignment with the arbors of the slitter machine. The knives and spacers can be slid either manually or mechanically between the shafts of the capstan and the arbors of the slitter machine.
Known capstans typically include a plurality of pairs of shafts which are aligned vertically with the arbors of the associated slitter machine but which extend in different orientations from the capstan frame. This permits an attendant to load knives and spacers onto one pair of shafts while another pair of shafts is aligned to transfer knives and spacers onto, or off of, the arbors of the slitter machine.
One drawback to such capstans relates to the alignment of the shafts with the corresponding arbors of the slitter. Very often, the heights of the shafts of the capstan are such that it is inconvenient for an attendant to load knives and spacers onto the shafts. Typically an attendant must lift the knives and spacers to load them onto an upper arbor and bend to load the knives and spacers onto a lower arbor. There remains a need in the art for a capstan designed to reduce the need for an attendant to have to repeatedly lift or bend in order to manipulate the tools on the capstan.
This need and others are addressed by a capstan for handling slitting tools comprising a base, a pivoting frame, an outer frame and a plurality fo shafts extending from the outer frame. The pivoting frame is supported by the base for pivotal movement about an axis. The outer frame is supported by the pivoting frame for translational movement along the axis. The plurality of shafts extends from the outer frame transversely to the axis.
The capstan further includes at least one axial actuator for raising and lowering the outer frame relative to the pivoting frame along the axis. The axial actuator permits an attendant to raise or lower the outer frame and thereby raise or lower the shafts to a convenient height for loading and unloading the knives and spacers. Optionally, the capstan includes a pivotal actuator for pivoting the pivot frame about the axis so as to align the shafts with arbors of an associated slitting machine.
The preferred actuators may operate hydraulically, electrically, manually, pneumatically or by any other suitable means which may be known to those of ordinary skill in the art. In accordance with one embodiment of the invention, the pivoting actuator comprises a hydraulic motor having a shaft mounting a pinion gear. The pivoting frame preferably mounts a ring gear engaged by the pinion gear so as to permit the motor to turn the pivoting frame. In accordance with another embodiment, the axial actuator comprises an axial actuator cylinder mounted by the base and an axial actuator piston. The axial actuator piston is slidably received in the axial actuator cylinder such that the axial actuator cylinder restrains the axial actuator piston for translational movement parallel to the axis. The axial actuator piston is positioned so as to press against the outer frame to raise or lower the outer frame in response to fluid pressure in the axial actuator cylinder.
Optionally, a pusher is provided to slide the knives and spacers between the shafts of the capstan and the arbors of the slitter machine. A preferred pusher comprises a pusher frame; a pusher plate; and a pusher actuator, most preferably hydraulic, for inducing the pusher plate to linear movement along one or more of the shafts of the capstan. Most preferably, the pusher includes one or more guide rod restraints and one or more guide rods constrained thereby to move linearly along the one or more shafts. One advantage of the optional pusher is that is relieves the attendant of the need to manually transfer the knives and spacers between the capstan and the slitter machine.
Therefore, it is one object of the invention to provide a novel capstan capable of vertical translational movement so as to permit its use at a height convenient to an attendant. It is another object of the invention to provide for the automatic transfer of the knives and spacers between the capstan and the slitter machine. These and other objects, features and advantages of the present invention will be described in further detail in connection with preferred embodiments of the invention shown in the accompanying drawings.